What 11 Billion People Mean for Earth's Animals

Below:

Next story in Science

Editor's note:By the end of
this century, Earth may be home to 11 billion people, the United
Nations has estimated, earlier than previously expected. As part
of a week-long series, LiveScience is exploring what reaching
this population milestone might mean for our planet, from our
ability to feed that many people to our impact on the other
species that call Earth home to our efforts to land on other
planets.Check
back hereeach day for the next
installment.

Until about 2,000 years ago, no human had set foot on Madagascar.
This wonderland of wildlife east of Africa is home to all of the
world's lemurs, a diverse group of primates, most of which have
foxlike faces and large eyes. Lemurs descend from animals that
arrived on the isolated island between 50 million and 60 million
years ago.

Since humans arrived, about 15 to 20 of these lemur species have
gone extinct, likely due to habitat loss and hunting, including
species whose males grew nearly as large as gorillas. But these
die-offs happened over the course of hundreds and thousands of
years. Humans are impacting the island at a much faster pace now.
As Malagasy populations rise, humans threaten the remaining
species of lemurs and thousands of other species with extinction
at an accelerating rate, said University of Illinois
primatologist Paul Garber.

Currently, 93 lemur species are endangered, critically
endangered or threatened, mostly due to the clearing of the
island's forests, according to the International Union for
Conservation of Nature (IUCN), a global environmental
organization. That's 91 percent of all lemur species for which
data is available.

Deforestation
has sped up in the second half of the 20th century, and in the
last 60 years, half of the island's remaining forests have been
cleared, according to a 2007 study in the journal Biology
Letters. During that time, the country's population has
quadrupled, according to the World Bank, a global financial
institution that offers loans to developing countries. But it's
not just the animals' homes that are vanishing — sometimes, the
animals themselves are taken. Since the breakdown of civil order
following a 2009 coup in the country, species such as collared
lemurs have been taken from forests to be sold in the illegal pet
trade, and they have been killed by hunters to be eaten as
bush meat, according to various news reports.

The plight of
Madagascar's lemurs is just one example of how a rising
population of humans is contributing to the
sixth-largest mass extinction in the history of the planet,
most biologists say. According to the IUCN, 20,000 species of
animals and plants are considered at high risk for extinction,
meaning there is a good chance they could die out if steps aren't
taken to ensure their survival. If species continue to die out at
current rates, more than
75 percent of all species currently on Earth could go extinct
within a few centuries, according to a 2011 study in the journal
Nature.

The extinction rate is estimated to be 100 to 1,000 times the
natural "background" rate as a result of human activities, said
Stacy Small-Lorenz, a conservation scientist at the Environmental
Defense Fund, an environmental group whose mission is to protect
the natural environment. The "background" rate is the rate
extinctions would be expected to occur in a world devoid of human
influence. "Human-induced climate
change, on top of other anthropogenic stressors like habitat
destruction, pollution and invasive species, is likely to
accelerate those extinctions," Small-Lorenz told LiveScience.

Some of Earth's most iconic animals, like the lemurs, are
threatened with habitat loss, displaced by growing human
populations and increased demand for agricultural products. This
threat has become even more palpable since the United Nations
issued a report this summer estimating the global
population would reach 11 billion by 2100, much faster than
previously estimated. Some good news is that the richest animal
diversity is found in a few places, which could make conservation
of these vital places easier. But it has to be made a priority,
which is often not the case, scientists say. [ What
11 Billion People Means for the Planet ]

"Every knowledgeable scientist is worried sick," said Paul
Ehrlich, a researcher and president of the Center for
Conservation Biology at Stanford University.

Habitat loss

One of the main ways humans have driven species to extinction is
by destroying their habitats.

Scientists are particularly concerned about habitat loss in a few
key places with the highest levels of biodiversity, such as the
Tropical Andes, the rainforests of Central America, the
Atlantic coastal forests of Brazil, Southeast Asia and many
Pacific Islands, central African rainforests and Madagascar.

The coastal forests of Brazil, for example, are almost as
biologically rich as the Amazon rainforest; about 60 percent of
the country's threatened animals live in these coastal forests,
according to the Nature Conservancy, an international
conservation group. For instance, just 1,500 golden lion tamarin,
a magnificent primate covered in red fur, are left in the wild,
the Smithsonian National Zoological Park reports. But this is
also where the bulk of Brazil's people live, and only 12 percent
of the original forests remain, much of it cut down in the past
few decades, the Nature Conservancy reported.

In Borneo and Sumatra, large companies are destroying forests and
replacing them with big swathes of palm tree monocultures,
threatening the future existence of orangutans, said Lee Hannah,
a senior fellow in climate change biology at Conservation
International, a global group devoted to saving endangered
animals and their habitats. There are only about 6,000 wild
orangutans left, and about 1,000 are being killed each year,
primarily from habitat destruction, according to the Orangutan
Project, an environmental group whose mission is to save the
animals.

The same is happening in Peru, where forests are being cleared to
make way for palm tree plantations, said Clinton Jenkins, a
conservation scientist at North Carolina State University. Such
palm trees are a rich source of palm oil, which is used in food
products and to make biofuels like biodiesel, a fuel with growing
demand as a source of "cleaner" energy. But several scientists
have pointed out that the cost of this fuel — destruction of
vital rainforests in South America, Southeast Asia and the
Pacific — is not counterweighed by any energy-saving
benefits.

Increased demand

Demand for the products comprising wildlife habitat — such as the
timber in forests, minerals in mountains or food grown on former
grasslands — represents a second major threat to animals. It's
not just sheer population growth that matters, but rather how
much people consume, said Richard Moss, a scientist at the Joint
Global Change Research Institute in College Park, Md. A good
example of this is China. The Chinese population has been booming
for years, but the recent increased consumption in the country
has significantly ramped up the drive for resources, within China
itself and around the world. From 1976 to 2003, for example,
booming demand for rubber led rubber farmers to clear 20 percent
of the rainforest of Xidai Prefecture, a lush region home to high
levels of biodiversity in south-central China, according to a
2007 study in the journal Biodiversity and Conservation.

But in China especially, and throughout Southeast Asia, demand
has also skyrocketed for the animals themselves, or at least
parts of their bodies. This has driven an epidemic of poaching —
especially of
elephants for ivory and rhinos for rhino horns — that appears
to be worsening, Hannah said. Tigers, lions and other big cats
have also increasingly been poached, due to demand for various
body parts like their iconic fur.

Rhino poaching, for example, has more than doubled since 2010
in South Africa, according to the country. And this year, rhinos
went extinct in the adjacent country of Mozambique, according to
news reports. It's hard to imagine that animals like African
elephants and rhinos will survive unless countries where they
live do more to protect them, Hannah said. Such measures will
have to include better protection by game wardens, and perhaps
more protected areas for wildlife, Jenkins said. [ 7
Iconic Animals Humans Are Driving to Extinction ]

The most effective way to fight poaching would be to decrease
demand, said Kenyan scientist and conservationist Richard Leakey
at a
conference on wildlife crime this May at Rutgers University.
One way to do that would be to better educate people in China and
Southeast Asia who buy these products, most of whom don't know
that elephants and rhinos are being driven to the brink of
extinction, said Leakey, who is the son of famed paleontologist
and fossil hunters Louis and Mary Leakey. When Richard Leakey
headed the Kenya Wildlife Service in 1989, he came up with the
idea to burn 12 tons of elephant tusks to bring public attention
to poaching, which had flared up in the late '80s. The ploy
worked, cutting the value of ivory by a factor of 30 and almost
single-handedly suppressing elephant poaching for nearly two
decades. Perhaps a similar gambit could work again, Leakey said,
although he didn't have any concrete suggestions.

A recent example from China may offer some hope, however.
Fishermen kill as many as 100 million sharks per year worldwide,
spurred in part by demand for shark fin soup, a traditional
Chinese delicacy. The fins are taken through a process called
shark finning, in which the animals' fins are hacked off and they
are thrown back into the ocean to slowly die. However,
China's taste for the dish may be fading : According to the
American environmental group WildAid, consumption of the soup is
down 50 to 70 percent in the last two years. Just a few years
ago, most Chinese didn't know that the dish came from sharks, as
its name translates to "fish wing" soup, according to the
Washington Post. But a series of public relations campaigns
appear to have helped spread the word. In 2006, for example,
WildAid enlisted the help of professional basketball player Yao
Ming to educate people on the shark finning process. A government
campaign against lavish banquets, where the soup was often
served, has also made a difference, the Post reported.

"It is a myth that people in Asia don't care about wildlife,"
Peter Knights, with WildAid, told the Post. "Consumption is based
on ignorance rather than malice."

Another clear-cut way to prevent poaching is to outlaw hunting,
said
Dereck Joubert, a National Geographic explorer-in-residence
and filmmaker. Botswana, Joubert's country of residence, outlawed
all hunting as of September 2013. When hunting was still allowed,
gunshots didn't necessarily attract a lot of attention, since
they could derive from legal hunting. But now, any shots are
likely to bring attention, so poaching is much more difficult,
Joubert said. Botswana is one of the few countries where
populations of lions and other large animals may be relatively
stable, he added.

Solutions

To prevent the expected rise in human population from wiping out
animal populations, more of the biologically important areas need
to be protected, most scientists agree. But there also need to be
more incentives to encourage conservation. People need to "take
steps to create an economic value for the lands where
biodiversity is concentrated," Moss said. "We don't really value
biodiversity
directly now, except when we exploit it."

Ecotourism is one way to do this. Turning hunting preserves into
ecotourism reserves creates more jobs while also protecting
wildlife, for example, Joubert said. On several land concessions
that Joubert and his wife Beverly co-own and have converted to
ecotourism reserves, the number of jobs has increased fivefold,
he said. These jobs also remain year-round, as opposed to only
during the five-month hunting season, Joubert added.

One of the best ways to protect areas is to support local groups
that have a stake in their native environment, Jenkins said. "Big
groups do get a lot of attention, but you simply have to have
local individuals who have a stake in the future of that region,"
Jenkins said. Examples include Brazil's Institute for Ecological
Research, which has wisely narrowed its focus on protecting a few
key areas in the country's Atlantic forests, he said. These
forests are home to 21 primates not found anywhere else, such as
the wooly spider monkey, according to the group. Areas the
institute protects include watersheds that provide drinking water
for São Paulo. Unlike some other organizations, they haven't
overextended themselves, Jenkins said. The group also offers
conservation training and classes to anybody who is interested in
conservation topics, allowing them to reach a broad audience, he
said.

How humans impact wildlife will depend largely on where future
development occurs. "Not all places are created equal," Jenkins
said. Some of the areas with the highest levels of diversity
contain many important species that appear nowhere else, so if
they are protected, some of the worse losses may be diverted,
Jenkins said. But many of these areas are already increasingly
threatened, even when they are not close to populated areas, he
added. There are many parks that preserve an impressive number
and range of wildlife, but one extreme example is Ecuador's
Yasuni National Park. The sprawling reserve contains 150
amphibian and 121 reptile species, making it the most diverse or
second most diverse place for each group of animals worldwide,
according to a 2010 PLOS ONE study.

Another primary way to conserve animals in the face of growing
populations is to simply make people aware of the decline of
various species. Recent analyses have shown that 80 percent of
people in China
have some ivory or would like to buy some, Joubert said. But
most of these people don't realize you have to kill an elephant
to get its ivory, and when they find out, they are generally
surprised and may no longer desire the substance, he added.
Dereck and Beverly Joubert have made more than 25 films about
large wildlife like lions, usually with a message about the
importance of conservation. In their latest film, "Game of
Lions," to debut Dec. 1 on Nat Geo Wild, they show just how hard
it is for male lions to survive — only one in eight survive to
adulthood — giving people a reason to not want to shoot them as
trophies, Dereck said. [ In
Images: 100 Most Threatened Species ]

Georgia Tech ecologist Marc Weissburg suggests that much of the
problem arises in cities. In the 21st century, for the first
time, a majority of humans live in urban areas. This could
theoretically be a more efficient way for people to live; by
minimizing the distance between people, you could reduce the
distance goods need to travel, and by concentrating waste
products, you could make them easier to treat and dispose of. But
this falls apart in practice: Food is grown in the countryside
and transported into cities, while waste products are mostly
taken out of the city and processed elsewhere. Cities need to
find ways to grow their own food, which would reduce the need for
the clearing of biodiversity-rich forests, far afield from
bustling metropolises, Weissburg said.

If materials such as rubber or palm oil could be manufactured in
cities, for example, there would be less incentive to cut down
pristine forests — like the ones in Borneo where orangutans live
— for agriculture, Weissburg said.

"If the planet is going to exist in a form that is habitable for
people, cities can't operate the way they operate right now,"
Weissburg said.

One solution would be to design cities to function more like
miniature ecosystems. Examples of this would include more urban
farming, producing food in the same area that is consumed, and
finding a way to reuse and process waste where it is generated,
Weissburg said.

Ultimately, however, saving animals will require more public
awareness and action, said Mark Costello, a researcher at New
Zealand's University of Auckland. "I hope that increased public
knowledge of declining nature will raise society's priority to
conserve biodiversity."